: Diabetes mellitus is the third most common metabolic disorder worldwide. The annual morbidity and mortality from the secondary complications of diabetes in the United States alone is staggering. The maintenance of euglycemia should prevent the development of or halt the progression of the secondary diabetic complications. Exogenous insulin therapy has been successful in producing long term euglycemia. Pancreatic tissue replacement has shown encouraging results but is limited to date by the shortage of donor organs, technical complications of the surgical procedures, the immune response of the host and infectious complications of the required immunosuppressive drug therapy. Bioartificial pancreases offer a potential solution by providing immunoprotection to the contained islet tissue. This would allow the use of xenogenic islet tissue without the need for immunosuppression. Previous bioartificial devices have failed due to poor glucose-insulin transfer kinetics and biocompatibility. Biosynthesis, Inc. has developed a device for the intraportal delivery of insulin which has functioned long term in this regard, and which may be applicable as an artificial pancreas. The applicants propose that canine pancreatic islets contained within the Biosynthesis, Inc. device will, in a physiologically relevant fashion, modulate glucose metabolism of pancreatectomized dogs, and protect the contained islets from the host immune response.